The document summarizes an experimental study on using phase change materials (PCM) for thermal control in buildings. Two identical test rooms were constructed - one with PCM panels in the walls and roof, and one without PCM as a reference. Sensors measured temperature and heat flux data. Results showed the PCM room had less temperature variation and a delayed temperature response compared to the reference room. Specifically, minimum indoor temperatures in the PCM room were up to 3°C higher. Additionally, installing PCM on the roof reduced indoor temperatures by around 2°C and lowered heat flux through walls. Therefore, the study demonstrates PCM can effectively increase thermal comfort in buildings.

1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 02 | Feb-2016, Available @ http://www.ijret.org 188
SOLAR THERMAL CONTROL OF BUILDING INTEGRATED PHASE
CHANGE MATERIALS: AN EXPERIMENTAL SURVEY
A. Mourid1
, M. Faraji2*
, M. El Alami3
, M. Najam4
, F. Berroug5
1,2,3,4
Hassan II University, Faculty of Sciences Ain Chock, Physics Department, LPMMAT Laboratory, Casablanca-
Morocco
5
Cadi Ayyad University, Faculty of Sciences Semlalia, Physics Department, LAEPT Laboratory, Marrakech- Morocco
(*)
Corresponding author Email: farajimustapha@yahoo.fr, phone: +212 0631756990
Abstract
In the present paper, we study experimentally the thermal behavior of phase change material (PCM) for thermal control of indoor
applications. The experimental setup consists of two full scale identical concrete cavities, situated in Faculty of Sciences Aïn
Chock in Casablanca- Morocco (33°36'N, 07°36'W). The first cavity incorporates paraffinic phase change material with melting
temperature of 22 °C and second cavity is built with alveolar bricks. The test cells are equipped by set of thermocouples and heat
flux meters connected to data logger. Thermal analysis for the two cubicles was conducted. The results show that inner
temperature swings decreases remarkably in the cavity with PCM with temperature minima 3 °C upper to the case without PCM.
On the other hand, there is time shift between PCM cavity and the reference cavity temperature oscillations. The integration of the
phase change material on the roof of the building reduces the temperature of internal walls as it has good thermal inertia. When
PCM panel covered the roof, solar heat transmission is reduced. This significantly reduces the ambient temperature of the cell.
This demonstrates the ability of PCM to increase the thermal comfort of buildings.
Keywords: PCM, Thermal Comfort, Building, Passive Solar Heating, Heat Storage. Melting, Solidification
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1. INTRODUCTION
Energy consumption for the air conditioning inside the
housing is becoming increasingly important for the modern
buildings. This type of construction generally uses
lightweight materials, low heat storage capacity, which
usually requires the use of artificial air conditioning. To
improve the thermal performance of the habitat in a passive
way, different types of phase change materials are used:
inorganic, organic and eutectic. These PCMs are incorporated
into different components of construction: walls, slabs and
floors. Phase change materials (PCM) can be used in building
using solar energy for heating or night cold for cooling.
During the process of melting and solidification of the PCM
incorporated in building structure, a large amount of energy
can be absorbed or released over a very small temperature
range, enabling PCM to act as a heat reservoir nearly
isothermal. Selecting PCM essentially concerns its melting
temperature, its latent heat capacity and cost. Different types
of PCMs and their characteristics are described in literatures.
Paraffin-based PCMs are commonly used in buildings
because of their appropriate melting temperature, their large
capacity for latent heat, stable chemical properties, non-
toxicity and low cost. One concern of using paraffin in
building constructions is its flammability. The wallboards are
cheap and widely used in a variety of applications, making
them very suitable for PCM encapsulation. However, the
principles of latent heat storage can be applied to any
appropriate building materials. The idea of improving the
thermal comfort of lightweight buildings by integrating
PCMs into the building structure has been investigated in
various research projects since before 1975 by Barkmann et
al.1
, Kedl et al.2
and Salyer et al. 3
, Shapiro et al.4,5
and by
Feldman et al.6
. Most of these attempts applied PCM macro-
capsules or direct PCM immersion processes. PCMs have
been incorporated into gypsum wallboards to provide passive
energy storage. For integration into the walls, the PCM layer
may be sandwiched between the inner and outer walls,
absorbed in porous concrete, or impregnated plasterboard7,8
.
Faraji et al.9
performed a numerical study of the thermal
performance of a concrete/paraffin/hydrate salt composite
wall used for heating management of building. The solar
energy absorbed by the wall is stored in a phase change
material (PCM). It was found that, when the PCM layer is set
closer to the inner face of the wall, thermal comfort
conditions are considerably improved compared to a concrete
wall without PCM. Castell et al.10
obtained energy
consumption reductions of 15 % when PCM was
implemented in building envelopes. The objective of the
present work is to evaluate the thermal performance of
envelope of residential buildings equipped with a phase
change material. An ordinary test cavity has been used as a
reference. The field trials were carried out with two identical
cells. The PCM was installed on the roof and/or in vertical
walls. The thermal performance of the walls was compared
with those of the reference cell by measuring their conductive
heat flux, internal walls temperatures and cells ambient
temperatures.

2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 02 | Feb-2016, Available @ http://www.ijret.org 189
Fig 1. (a)
Fig 1. (b)
Fig 1. (c)
Figure 1: Experimental setup full scale size: cubicles
construction stages (a) under building, (b) finish. (c) PCM
panels.
2. EXPERIMENTAL FACILITY
2.1. Experimental setup
Figure 1-a,b shows the experimental setup located in
Casablanca, Morocco (33°36'N, 07°36'W). It consists of two
full scale cubicles with the same internal dimensions
(2.8x2.8x2.8 m), equipped with glazed window (1x1 m) and a
door (2x1 m), in the north wall. The constructive systems of
these rooms are:
- Reference cubicle: built with alveolar bricks system
based on two layers of bricks as follows: 2 cm mortar, 7
cm red bricks, 14 cm air gape, 7 cm red bricks and 1 cm
mortar, successively. The roof was built by full paving
stone concrete.
- PCM cubicle: built as the previous cubicle adding a PCM
panels in the inner faces of the vertical walls and on the
roof. PCM consist of Energain paraffin panels, Figure 1-c.
2.2. Phase Change Material (PCM)
The phase change material used is Rubitherm-Energain,
product manufactured by Dupont de Nemours Company
(Luxembourg). This PCM is a rectangular panel with
dimensions of 1x1.2 m and embedded in a thin aluminum
cover. The shape of the PCM material is flexible aluminum
sheet of 5.26 mm, Figure 1 (c). The panel contains 40 % of
solid compound (copolymer ethylene) and 60 % of paraffin. It
is characterized by a melting temperature of 21.7°C and an
enthalpy of 70 kJ/kg. The thermal conductivity is 0.18 Wm-
1
.K-1
in solid phase and 0.14 Wm-1
.K-1
in liquid phase.
Rubitherm-Energain PCM was selected to be used in the
cubicle because it store and release large quantities of thermal
energy at nearly constant temperature, The use of one
Energain panel of 5 mm thickness is equivalent to 30 mm of
concrete. It is chemically inert, long life product and stable
performances during phase change cycles also, the melting
temperature is close to human comfort. Table 2 summarizes
the main thermal properties of the PCM.
Table 1 summarizes the geometrical dimensions of the
cubicle walls.
Table 1: Envelop materials (from interior to exterior) (a),
Vertical walls thermal properties (b), Roof structure and
materials properties (c)
Wall Material Thickness(mm)
Roof Mortar 20
Concrete 120
Mortar 20
Vertical wall PCM 5.26
Air layer 14
Mortar 10
Brick 70
Air layer 140
Brick 70
Mortar 10
Floor Mortar 100
Plaster 50
Concrete 100
Calc 300
Glazed
façade
Glass 3
(a)

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Volume: 05 Issue: 02 | Feb-2016, Available @ http://www.ijret.org 190
Mortar Alveolar Air Alveolar Mortar
e (cm) 1 7 14 7 1
cp (kJ/kg.k) 0.84 0.79 1.23 0.79 0.84
λ (W/m.k) 1.15 0.47 0.09 0.47 1.15
(b)
Mortar Full paving
concrete(roof)
e (cm) 20 15
cp (kJ/kg.k) 0.84 0.92
λ (W/m.k) 1.15 1.75
(c)
2.3. Instrumentation and Measurements
The cells are instrumented with 75 thermocouples K-type
(2/10 mm) with an accuracy of ±2%. They are carefully
welded, ensuring that the weld is of the same diameter that
the two wires. Then, they are calibrated and the assembly is
connected to a data acquisition device, Figure 2-a. Note that
the thermocouples are distributed in order to access to the
average temperatures of all the walls and the indoor
temperature of the cells.
We have also conducted heat flux density measurements
through the walls of the room with heat flux captors, Figure
2-b, having an accuracy of ±3 % and a 0.3 s response time.
The considered case is a room with one person and personal
computer, corresponding to 300 W internal gains11
.
Are registered with 10 minutes frequency:
- Internal walls temperatures and also external temperature.
- Internal ambient temperature (at a height of 1.5 m).
- Heat fluxes at the cubicles faces.
(a)
(b)
Figure 2: Thermocouples and Data Acquisition System (a).
Heat flux sensor (b)
2.4. Meteorological Data
The experiments were carried out for free external radiations
and temperature conditions during March and August 2014.
Meteorological station, fixed on the roof of the test cells, was
used to register the outdoor ambient temperature, solar
radiation, wind velocity and wind direction and relative
humidity. All data are stored in a desk computer using data
logger.
3. RESULTS AND DISCUSSION
The results from the experimental test in the cubicles with
and without PCM were obtained from 2014 during the
periods of Mars, 09 to 13: heating period, and August, 26 to
31: air refreshing period.
3.1. Heating Period: PCM in Vertical Walls
Figure 3 analysis shows that minimum outdoor temperatures
are obtained during the night. On average, temperatures
minima and maxima range between 10 °C and 23 °C,
respectively, and the ambient temperature swings between
these extremes. During the first 7 hours every day, solar
radiations rises and the ambient outdoor temperature
increases. Solar radiation reaches a maximum value, 720
W/m2
and falls to zero at the sunset. Casablanca city climate
is characterized by significant temperature fluctuations with
lower nocturnal values of temperature. None controlled
building will demand more energy for heating purpose.
Figure 3: Time wise variations of the external ambient
temperature and solar radiations, (Casablanca, Morocco
33°36'N, 07°36'W)
Table 2: Thermal properties of the Energain PCM12
Parameter Value
Melting point 21.7C
Combined Heat storage capacity (latent and
sensible heat in a temperature range of 14 to
29°C)
>170
kJ/kg
Specific heat capacity >70
kJ/kg K
Conductivity - solid phase
Conductivity - liquid phase
0.18
W/m K
0.14
W/m K
Time(Hours)
Temperature(°C)
SolarradiationsW/m2
0 6 12 18 24 30 36 42 48 54 60 66 72
10
12
14
16
18
20
22
24
26
28
30
32
34
0
100
200
300
400
500
600
700
800Outdoor temperature
Solar radiations

4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 02 | Feb-2016, Available @ http://www.ijret.org 191
Figure 4: Time wise variations of the external ambient
temperature and south walls temperature for cubicles with
and without PCM, (Casablanca, Morocco 33°36'N, 07°36'W)
Figure 4 shows the time variations of the temperature of south
wall of both cubicles. Data analysis shows that the thermal
reduction is slower in the PCM cubicle case, since it has
stored more heat (latent) during a day. Remember that
ambient temperature vary between 10 °C to 23 °C, but the
building walls receive also solar irradiative heat flux absorbed
by the concrete having solar absorption coefficient of 0.8,
combined with internal loads and convective heat flux. A
thermal gain leads to the increase of the PCM temperature to
its melting point. During the night, when the PCM undergoes
phase change, the slop of PCM wall temperature curve
weakens because the solidification of PCM occurs at a nearly
constant temperature. Sensible heat dissipation is disabled
and the decrease of the PCM cubicle nocturnal temperature is
shifted. Composite PCM-Concrete walls can be considered as
an important heat storage device. The stored heat during a
day is naturally released for heating needs in the following
cold night with less temperature fluctuations.
Figure 5: Outdoor and indoor ambient temperatures for
cubicles with and without PCM on the roof
3.2. Refreshing Period: PCM on the Roof
In order to minimize heat gain in the summer, PCM panels
were placed on the roof of the test cell. The flow to be
transmitted by conduction to the inside will be converted by
the PCM as latent heat of fusion. To demonstrate this process,
we will compare the internal ambient temperature of the PCM
room to those of the reference room. The results were
obtained from 26 to 31 August 2014. Figure 5 sketches the
experimental result according to the indoor ambient
temperatures for cubicles with and without PCM on the roof.
It was emerged that, the inner ambient temperature of the cell
without PCM is practically identical with the outside
temperature because of low thermal inertia of local. For the
case of cubicle with PCM roof, the room has good thermal
inertia and PCM contributes to refresh the air and an inner
temperature is decreased about 2 °C, because that, during the
melting of the PCM, sensible heat gain is disabled and the
increase of the PCM cubicle diurnal temperature is shifted.
During the night, the cancelation of solar radiations and the
fall of the external temperature promote the freezing of PCM.
Also, sensible heat accumulated during the hot day is released
to the exterior and to the PCM at nocturnal phase. An
important amount of cold is stored in the crystallized PCM at
night and will be used passively to refreshing the room during
the following day.
Figure 6: Evolution of conductive thermal gradients via the
cubicles south wall
Figure 6 represents the conductive thermal gradients via the
south walls. It is found that the heat flux exchanged by
conduction through this wall is very important in the PCM
cell. Indeed, there are very significant reductions in solar
energy gain through the ceiling with PCM. This significantly
reduces the ambient temperature of the cell as shown in
Figure 5, which causes an increase in heat flow through the
vertical walls. The heat flux flow reaches 2.5 W/m2
in the
reference and cell exceeds 4 W/m2
in the PCM cell. In the
case of roof with PCM thermal gradient can be negative at
night because the indoor air remains warmer than the outdoor.
4. CONCLUSION
Experimental investigation of the thermal performance of
composite concrete/PCM cubicles constructed within the
Faculty of Science Ain Chock in Casablanca city, Morocco,
equipped with a phase change material, in vertical walls and
on the roof, was performed. The results showed a significant
Time(Hours)
Temperature(°C)
0 6 12 18 24 30 36 42 48 54 60 66 72
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34 With PCM
No PCM
Outdoor temperature
Time(Hours)
Temperature(°C)
0 6 12 18 24 30 36 42 48 54 60 66 72
26
27
28
29
30
31
32
33 With PCM
No PCM
Outdoor temperature
Time(Hours)
Heatflux(W/m2)
0 6 12 18 24 30 36 42 48 54 60 66 72
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5 With PCM
No PCM

5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 05 Issue: 02 | Feb-2016, Available @ http://www.ijret.org 192
reduction of indoor temperature fluctuations due to
absorption and release of solar gains in the composite wall in
conjunction with melting of the PCM. The results showed
that thermal load of the cubicle containing PCM was reduced
compared to the case without PCM with more constant
conditions during the heating period. This study showed also
that the integration of PCM in the roof lowers the temperature
of inner side walls and reduces the amplitude of the
oscillations of the temperature of about 2 °C during the air
refreshing period. It was emerged that the cubicle with
PCM/concrete walls is able to provide good performance.
The thermal conditions of the indoor environment achieved
with the presence of PCM panels were considerably improved
compared to cubicle without PCM.
ACKNOWLEDGEMENT
The present work was financially supported by the Innotherm
R&D project –IRESEN-Morocco.
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